富氧条件下等离子体协同改性NaY分子筛催化分解NO_x研究

用不同浓度的Cu、Ce和La离子交换Na Y分子筛,对比了不同改性条件下等离子体协同分解NO_x的性能.实验结果表明:Cu是NO_x催化分解的主要活性组分,对于8%Cu-Na Y催化剂,当放电电压为10 k V,放电功率为7.6 W时,NO_x转化率可达46.3%,反应产物中没有NO_2,只有11 ppm的N_2O.Ce的加入可以有效提高催化剂催化活性,对于5%Ce-8%Cu-NaY催化剂,当放电电压为7.8 kV,功率为3.6 W时,NO_x转化率可达67.3%.La的加入同样可以使催化剂活性上升,但不同La含量催化剂的NO_x转化率相差较小.     

城市生物多样性保护与生态系统服务供给

生物多样性和生态系统服务是人类生存和社会经济可持续发展的物质基础,城市化过程中,由于人类过度密集地聚集于一个区域,集约的社会经济活动不断侵占生态空间,对其他生物产生驱逐效应,造成生态恶化,生物多样性丧失进而导致生态系统提供的人类福祉下降,这使得在城市内部如何合理配置生态资产,保护生物多样性和提供充足生态系统服务成为城市发展过程中必须面对的一个挑战。建议城市周边进行生态系统的自然化再造与保护,对城市已有生态系统近自然化改造,城区绿地多样化生态景观建造,逐渐推进生态资源资产化过程。     

基于改进DRASTIC模型、GIS和层次分析法(AHP)的地下水U(VI)污染风险评价

以某铀尾矿库为例,应用层次分析法(AHP)对DRASTIC进行改进,得出AHP-DRASTICLL模型,并构建了综合指数体系,在此基础上,基于GIS平台对某铀尾矿库区地下水受U(VI)污染风险进行了评价和污染区的污染风险划分。由地下水风险区划图得出尾矿库周围与砂卵砾石层区风险较高,丘陵地带风险较低,其结果较好地反映了实际的污染风险现状。     

Impact of dissolved organic matter on the photolysis of the ionizable antibiotic norfloxacin

Norfloxacin (NOR), an ionizable antibiotic frequently used in the aquaculture industry, has aroused public concern due to its persistence, bacterial resistance, and environmental ubiquity. Therefore, we investigated the photolysis of different species of NOR and the impact of a ubiquitous component of natural water — dissolved organic matter (DOM), which has a special photochemical activity and normally acts as a sensitizer or inhibiter in the photolysis of diverse organics; furthermore, scavenging experiments combined with electron paramagnetic resonance (EPR) were performed to evaluate the transformation of NOR in water. The results demonstated that NOR underwent direct photolysis and self-sensitized photolysis via hydroxyl radical (·OH) and singlet oxygen (¹O₂) based on the scavenging experiments. In addition, DOM was found to influence the photolysis of different NOR species, and its impact was related to the concentration of DOM and type of NOR species. Photolysis of cationic NOR was photosensitized by DOM at low concentration, while zwitterionic and anionic NOR were photoinhibited by DOM, where quenching of UOH predominated according to EPR experiments, accompanied by possible participation of excited triplet-state NOR and ¹O₂. Photo-intermediate identification of different NOR species in solutions with/without DOM indicated that NOR underwent different photodegradation pathways including dechlorination, cleavage of the piperazine side chain and photooxidation, and DOM had little impact on the distribution but influenced the concentration evolution of photolysis intermediates. The results implied that for accurate ecological risk assessment of emerging ionizable pollutants, the impact of DOM on the environmental photochemical behavior of all dissociated species should not be ignored.     

塔克拉玛干沙漠未来的规划发展及前景设想

塔克拉玛干沙漠,是全世界第二大流动沙漠。整个沙漠东西长约1 000 km,南北宽约400 km,总面积337 600km2。目前,塔克拉玛干沙漠有两条沙漠公路贯通南北,正在规划设计中的是塔克拉玛干沙漠第三条沙漠公路。塔克拉玛干沙漠周边有5个地级首府市,东面是库尔勒市,北面是阿克苏市,西面是喀什市和阿图什市,南面是和田市。沙漠边缘有阿拉尔市、图木舒克市、和田市、巴楚县、麦盖提县、莎车县、泽普县、叶城县、皮山县、墨玉县、洛浦县、策勒县、于田县、民丰县、且末县、若羌县、尉犁县、轮南镇等。这些城市常年经受着沙尘暴及恶劣气候环境的影响,人们的生活环境苦不堪言,有效地治理沙漠恶劣的气候环境,治理沙尘暴,是改善当地恶劣气候环境,改善老百姓生活生存条件的根本所在。     

Enhanced U(VI) bioreduction by alginate-immobilized uranium-reducing bacteria in the presence of carbon nanotubes and anthraquinone-2,6-disulfonate

Uranium-reducing bacteria were immobilized with sodium alginate, anthraquinone-2, 6-disulfonate (AQDS), and carbon nanotubes (CNTs). The effects of different AQDS-CNTs contents, U(IV) concentrations, and metal ions on U(IV) reduction by immobilized beads were examined. Over 97.5% U(VI) (20 mg/L) was removed in 8 hr when the beads were added to 0.7% AQDS-CNTs, which was higher than that without AQDS-CNTs. This result may be attributed to the enhanced electron transfer by AQDS and CNTs. The reduction of U(VI) occurred at initial U(VI) concentrations of 10 to 100 mg/L and increased with increasing AQDS-CNT content from 0.1% to 1%. The presence of Fe(III), Cu(II) and Mn(II) slightly increased U(VI) reduction, whereas Cr(VI), Ni(II), Pb(II), and Zn(II) significantly inhibited U(VI) reduction. After eight successive incubation-washing cycles or 8 hr of retention time (HRT) for 48 hr of continuous operation, the removal efficiency of uranium was above 90% and 92%, respectively. The results indicate that the AQDS-CNT/AL/cell beads are suitable for the treatment of uranium-containing wastewaters.     

Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid

Understanding the effects of oxalic acid(OA) on the immobilization of Pb(Ⅱ) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(Ⅱ) by KH2PO4, phosphate rock(PR), activated phosphate rock(APR) and synthetic hydroxyapatite(HAP) at different phosphate:Pb(P:Pb) molar ratios(0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or Ca Cl2, Community Bureau of Reference(BCR) sequential extraction and toxicity characteristic leaching procedure(TCLP)methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after120 days was reduced by 100% when soils were amended with APR, HAP and HAP + OA, and the TCLP-Pb was 5 mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was 5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.     

膨润土负载纳米铁的改性及对水中As(Ⅴ)的吸附

用十六烷基三甲基溴化铵(CTMAB)对膨润土负载纳米零价铁(Bent-n ZVI)进行表面改性,得到表面改性膨润土负载纳米铁(Bent-n ZVI)/CTMAB。通过SEM、Zeta电位和中位径d(50)分析,与膨润土(Bent)、改性膨润土(CTMAB-Bent)、Bent-n ZVI进行了对比,结果表明:相比Bent-n ZVI,(Bent-n ZVI)/CTMAB中的纳米铁颗粒更为分散且呈链状分布,d(50)仅为5.21μm,并且Zeta电位为+0.65 m V,更易静电吸引和吸附阴离子As O43-。4种材料的除砷结果亦表明其中(Bent-n ZVI)/CTMAB去除率最高,达到了93.9%。光电子能谱(XPS)分析表明(Bent-n ZVI)/CTMAB的除砷产物中只有As(Ⅴ),并不存在其还原态As(Ⅲ),说明(Bent-n ZVI)/CTMAB是通过吸附作用去除As(Ⅴ)。     

“为无告的大自然代言!” 新《环境保护法》环境公益诉讼第一案开庭

<正>新《环境保护法》实施后的首例环境民事公益诉讼案件"福建南平生态破坏案",于2015年5月15日在福建省南平市中级人民法院公开开庭审理。2015年1月1日,新《环境保护法》生效当天,南平生态破坏案的原告方,民间环保组织自然之友和福建绿家园得到南平中院的案件受理通知书,被誉为新《环境保护法》环境公益诉讼第一案。时隔五个多月,该案进入公开开庭审理环节。     

自然之友

自然之友成立于1994年,多年来秉着"真心实意,身体力行"的核心价值观,推动中国的环境启蒙、生态保护、环境法治和绿色公民成长,是最具公信力的专业环境保护公益组织之一。自然之友在北京拥有核心工作团队,在全国15个城市分布17个志愿性的会员小组,并依托具体业务推动建立多个行动平